Myungkil Kim

Molecular characteristics of two laccase from the basidiomycete fungus Polyporus brumalis

Two laccase cDNAs, pblacl and pblac2, were cloned from a white-rot fungus strain, Polyporus brumalis (KFRI 20912). The cloned cDNAs consisted of 1,829 bp and 1,804 bp, and their open reading frames encoded proteins of 520 and 524 amino acids, with calculated molecular masses of approximately 55.9 kDa and 56 kDa, respectively. The deduced amino acid sequences of each protein showed 70% similarity. The copper binding regions were conserved in both proteins, as in other fungal laccases. RT-PCR analysis revealed that the transcript levels of the two laccases increased progressively in shallow stationary culture liquid medium. The transcript level of each laccase was induced when the fungus was exposed to di-butyl phthalate (DBP), suggesting that the two laccases are involved in DBP degradation. The overexpression of the pblac1 gene was derived by the promoter of a gene for glyceraldehyde-3-phosphate dehydrogenase, using a homologous system. The activity of laccase in the transformants was significantly higher than that of the wild type. The identification of these laccase cDNAs was a first step to characterize the molecular events related to the lignin degradation ability of this basidiomycetous fungus, as well as the degradation of many recalcitrant xenobiotics.

Biodegradation of Methoxychlor and Its Metabolites by the White Rot Fungus Stereum hirsutum Related to the Inactivation of Estrogenic Activity

The white rot fungus Stereum hirsutum was used to degrade methoxychlor [2,2,2-trichloro-1,1-bis(4-methoxyphenyl)ethane] in culture and the degraded products were extensively determined. The estrogenic activity of the degraded products of methoxychlor was examined using cell proliferation and pS2 gene expression assays in MCF-7 cells. S. hirsutum showed high resistance to methoxychlor 100 ppm, and the mycelial growth was fully completed within 8 days of incubation at 30°C. Methoxychlor in liquid culture medium was gradually converted into 2,2-dichloro-1,1-bis(4-methoxyphenyl)ethane, 2,2-dichloro-1,1-bis(4-methoxyphenyl)ethylene, 2-chloro-1,1-bis(4-methoxyphenyl) ethane, 2-chloro-1,1-bis(4-methoxyphenyl) ethylene, and 1,1-bis(4-methoxyphenyl)ethylene, indicating that methoxychlor is dominantly degraded by dechlorination and dehydrogenation. MCF-7 cells were demonstrated to proliferate actively at the 10−5 M concentration of methoxychlor. However, cell proliferation was significantly inhibited by the incubation with methoxychlor culture media containing S. hirsutum. In addition, the expression level of pS2 mRNA was increased at the concentration (10−5 M) of methoxychlor. The reductive effect of S. hirsutum for methoxychlor was clear but not significant as in the proliferation assay.

Transcriptomic analysis of the white rot fungus Polyporus brumalis provides insight into sesquiterpene biosynthesis.

Object of this study was to identify genes and enzymes that are involved in sesquiterpene biosynthesis in the wood rotting fungus, Polyporus brumalis. Sesquiterpenes, β-eudesmane and β-eudesmol, were produced by the mycelium of P. brumalis cultured in modified medium. However, theses final products were not observed when the fungus was grown in potato dextrose medium. We used next generation sequencing (NGS) to identify differentially expressed genes (DEGs) related to terpene metabolism. This approach generated 25,000 unigenes and 127 metabolic pathways that were assigned to Kyoto Encyclopedia Genes Groups (KEGG). Further analysis of samples from modified medium indicated significant upregulation of 8 unigenes involved in the mevalonate (MVA) and methylerythritol phosphate (MEP) biosynthetic pathways. These pathways generate isopentenyl pyrophosphate (IPP) and farnesyl pyrophosphate (FPP), which are precursors for the synthesis of sesquiterpenes. Furthermore, genes encoding germacrene A synthase, which facilitate the cyclization of FPP, were only differentially expressed in mycelium from fungi grown in modified medium. Our data provide a resource for studying the molecular mechanisms underpinning sesquiterpene biosynthesis and terpene metabolism.

Control of Diatrype stigma Occurred on the Bed-log of Shiitake Using Wood Vinegar, Plant Extracts and Fungicides

목초액, 잣나무추출물, 후추열매추출물 및 살균제를 이용해서 표고 골목에 발생하는 주홍꼬리버섯을 방제하고자 하였다. 식물추출물 선발시험결과, 목초액 35,000 ppm에서 균사생장이 완전히 억제되었고 25,000 ppm에서 자낭포자의 발아가 관찰되지 않았다. 그리고 잣나무추출물 200 ppm과 후추열매추출물 1,000 ppm에서 각각 98.9%와 95.9%의 자낭포자발아억제율을 보였다. 살균제 선발시험 결과, benomyl, carbendazim, thiabendazole 등의 최소억제농도(MIC)는

Whole-genome de novo sequencing of wood rot fungus Fomitopsis palustris (ATCC62978) with both a cellulolytic and ligninolytic enzyme system

0{\sim}0.4\;{\mu}g\;a.i./m{\ell}

Development and Molecular Characterization of Novel Polymorphic Genomic DNA SSR Markers in Lentinula edodes

였다. Difenoconazole은

Phanerochaete chrysosporium Multienzyme Catabolic System for in Vivo Modification of Synthetic Lignin to Succinic Acid

0.08%\;{\mu}g/m{\ell}

Changes in Activities of Lignin Degrading Enzymes and Lignin Content During Degradation of Wood Chips by Polyporus brumalis

농도에서 자낭포자 발아를 98.9% 억제했다. 살균제에 의한 표고균사생장억제율 조사 결과, 저온성, 중온성, 고온성균주 간에 차이가 거의 없는 것으로 나타났다. Benomyl, carbendazim, thiabendazole, thiophanate-methyl 등은 높은 농도에서도 비교적 낮은 억제율을 보였으나, tebuconazole은

Biodegradation of dibutylphthalate by white rot fungi and evaluation on its estrogenic activity

0.4\;{\mu}g\;a.i./m{\ell}

Dibutyl phthalate biodegradation by the white rot fungus, Polyporus brumalis

농도에서도 80% 이상의 억제율을 보여 표고균에 좋지 않은 영향을 미치는 것으로 나타났다. 목초액 및 식물추출물과 살균제를 골목에 살포한 결과 목초액 150,000 ppm이 주흥꼬리버섯의 포자퇴형성 전 처리에서 72.7%의 방제가를 보였고 포자퇴형성 후 처리에서 목초액 70,000 ppm과 thiophanate-methyl 1,000 ppm이 각각 58.1%와 52.3%의 방제가를 보였다. 【Attempts were made to control Diatrype stigma occurred on the bed-log of Shiitake using wood vinegar, Pinus koraiensis extract, Piper nigrum extract, and fungicides. Mycelial growth of D. stigma was inhibited completely at 35,000 ppm and no ascospore germinated at 25,000 ppm wood vinegar. Inhibition rates of Pinus koraiensis extract (200 ppm), and Piper nigrum extract (1,000 ppm) to ascospore germination were 98.9% and 95.9%, respectively. In fungicide selection, minimum inhibitory concentration (MIC) of benomyl, carbendazim, and thiabendazole ranged